an investment has an installed cost of $578,382. the cash flows over the four-year life of the investment are projected to be $207,584, $251,318, $199,674, and $167,313. if the discount rate is zero, what is the npv? note: do not round intermediate calculations and round your answer to the nearest whole number, e.g., 32. if the discount rate is infinite, what is the npv? note: a negative answer should be indicated by a minus sign. do not round intermediate calculations and round your answer to the nearest whole number, e.g., 32. at what discount rate is the npv just equal to zero?